1. Field of the Invention
This invention relates to a wood-based decorative article of composite construction having a veneer arranged on the front surface side thereof and a synthetic resin arranged on the rear surface side thereof and used for decoration of interior equipment for automotive vehicles, furniture, household electrical appliances, and so forth, as well as to a method of manufacturing the same.
2. Description of the Prior Art
Conventionally, a method of manufacturing a wood-based decorative article of the above-mentioned kind was disclosed e.g. in Japanese Patent Publication (Kokoku) No. 1995-115380. As shown in FIG. 1, according to the manufacturing method, first, a veneer 51 formed of thinly sliced wood is made available (FIG. 1(a)), and then a reinforcing member 53 formed e.g. of a thin metal plate is bonded to the rear surface of the veneer 51 by an adhesive 52 to thereby produce a veneer sheet 54, and a coating process including coloring or dyeing and top coating is performed on the veneer 51 of the veneer sheet 54 (FIG. 1(b)). The coloring/dyeing of the veneer 51 is performed so as to achieve a more beautiful finish by enhancing the grain of the veneer 51. Then, the veneer sheet 54 is set in a mold, not shown, and a molten synthetic resin is injected onto the rear surface of the veneer sheet 54, whereby a substrate 55 made of the synthetic resin is formed on the rear surface of the veneer sheet 54 in a manner integrated with the veneer sheet 54, and at the same time a wood-based decorative article 56 is obtained which is molded as a whole to have a predetermined shape (FIG. 1(c)).
The other conventional methods of manufacturing a wood-based decorative article include, for instance, one illustrated in FIG. 2. According to this manufacturing method, first, two front and rear veneers 61, 62 each formed of thinly sliced wood and a non-woven fabric 63 interposed therebetween are laid one upon another and bonded to each other by using an adhesive, not shown, to make a veneer sheet 64 (FIG. 2(a)). The front veneer 61 functions as a decorative layer, and the non-woven fabric 63 as a reinforcing layer for reinforcing the front veneer 61 which is fragile. Further, the rear veneer 62 functions as an anchoring layer for anchoring a synthetic resin injected onto the rear surface thereof at the following step. Then, after setting the veneer sheet 64 in a mold, not shown, the molten synthetic resin is injected onto the rear surface of the veneer sheet 64 and molded to form a substrate 65 on the rear surface of the veneer sheet 64 in a manner integrated with the veneer sheet 64 (FIG. 2(b)). The substrate 65 is provided for ensuring the strength and rigidity of the wood-based decorative article 67, and the synthetic resin forming the substrate 65 is opaque. Then, top coating is performed on the front surface of the veneer sheet 64, i.e. on the front veneer 61 to form a topcoat layer 66, thereby completing the wood-based decorative article 67 (FIG. 2(c)). The topcoat layer 66 is usually given a polished finish by applying a thick coat e.g. of a polyester coating material onto the front veneer 61 through overcoating performed by multiple coating processes, including an undercoating process, an intercoating process and a finish coating process, while repeatedly carrying out polishing processes for polishing films formed by the respective coating processes.
However, in the conventional manufacturing method shown in FIG. 1, the reinforcing member 53 is bonded to the veneer 51 by the adhesive 52, and then subjected to coating such as coloring or dyeing. Therefore, before the coloring or dyeing is carried out, the veneer 51 has its vessels and fibers impregnated with the adhesive 52. As a result, a coloring agent or a dye is hindered by the adhesive 52 from sufficiently penetrating into the vessels and fibers of the veneer 51, which makes it impossible to carry out sufficient coloring or dyeing to obtain a beautiful wood grain.
Further, the wood-based decorative article 56 is a composite of the veneer 51 and the substrate 55 having different physical properties, and hence tends to suffer from the following problem: The expansion factor of the veneer 51 in relation to humidity is larger than that of the synthetic resin forming the substrate, and hence the dimensional change of the veneer 51 due to a change in humidity is larger. However, since the veneer 51 and the substrate 55 are integrally joined to each other, the veneer 51 is restrained from the dimensional change. For this reason, when the wood-based decorative article 56 is placed in a highly humid environment, a compressive stress acts on the veneer 51, while a tensile stress acts on the substrate 55, which can cause cracking or warpage of the veneer 51.
On the other hand, in the conventional manufacturing method illustrated in FIG. 2, in order to achieve a polished finish, it is required to form the thick topcoat layer 66 through overcoating by repeatedly carrying out the application of the top coating material and polishing of the same. Therefore, the number of man-hours required for the top coating process and the material cost are increased, which leads to increased manufacturing costs. Further, since it is required to provide not only the front veneer 61 but also the rear veneer 62 as the anchoring layer for anchoring the injected synthetic resin, the number of man-hours required to make the veneer sheet is further increased, and the use of the two relatively expensive veneers causes an increase in the material cost, which also leads to the increased manufacturing costs.
Moreover, while the front surface is subjected to the top coating process to be given a polished finish, it is only the front veneer 61 arranged with the substrate 65 as its background that can be seen through the topcoat layer 66. For this reason, the front veneer 61 lacks the feel of depth and the feel of gloss (shiny brightness which looks different depending on viewing angles), and hence only a monotonous finish can be obtained. For the same reason, the design of the wood-based decorative article 67 is substantially determined by the front veneer 61, so that as long as the front veneer 61 remains unchanged, the design of the wood-based decorative article 67 is basically unchanged to provide only a substantially fixed design.